Hand-held power tool hammer mechanism

ABSTRACT

A hand-held power tool hammer mechanism, having a hammer device, can be driven by a piston via a gas volume. The hammer device has at least one decoupling element, which is provided for dimensionally decoupling a main hammer body of the hammer device, and has a coupling between the decoupling element and the main hammer body, which is provided to couple the main hammer body to the decoupling element in an at least largely synchronous fashion during a flight phase of the main hammer body.

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2005 019 710.8, filed Apr. 28, 2005. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The invention relates in particular to a hand-held power tool hammer mechanism.

There are already known hand-held power tool hammer mechanisms that have a hammer device that can be driven by means of a piston via a gas volume. The hammer device is essentially cylindrically embodied and has a round hammer device surface or effective surface oriented toward the gas volume. In order to achieve the most compact possible hand-held power tool hammer mechanism, it is standard to provide a hammer device characteristic value of approx. 160 mm³/g, which is composed of a maximum hammer device surface dimension—such as a maximum hammer device surface diameter or hammer device effective surface diameter—cubed and divided by the hammer device mass. During operation, a maximum pressure of approx. 15 bar occurs in the gas volume.

SUMMARY OF THE INVENTION

The invention therefore is based on a hand-held power tool hammer mechanism with a hammer device that can be driven by means of a piston via a gas volume.

According to one embodiment, the hammer device has at least one decoupling means, which is provided for dimensionally decoupling a main hammer body of the hammer device, and at least one coupling between the decoupling means and the main hammer body, which is provided to couple the main hammer body to the decoupling means in an at least largely synchronous fashion during a flight phase of the main hammer body. The term “main hammer body” is understood in particular to mean a part of the hammer device that makes up at least a large part of the mass of the hammer device and/or acts on a tool directly or by means of a hammer pin. The term “dimensional decoupling” is understood in particular to mean a decoupling from at least one standpoint so that the dimensions of the main hammer body preferably have at least one degree of freedom. The term “flight phase” is understood in this context in particular to mean a movement of the main hammer body generated by the piston and oriented toward a tool or toward a hammer pin and toward the piston itself.

A corresponding embodiment according to the invention permits a further improvement of the main hammer body and/or the entire hammer device, from at least one standpoint in terms of its function. In addition to the hammer device, a hammer pin device can in particular also include a decoupling means for dimensionally decoupling a main hammer pin body, which makes it possible to also achieve additional degrees of freedom with regard to the design of the hammer pin device. In this context as well, the term “main hammer pin body” is understood in particular to mean a part of the hammer pin device that makes up at least a large part of the mass of the hammer pin device and/or cooperates directly with a tool and/or with the hammer device.

The decoupling means can be embodied in a variety of forms; preferably, it is situated in the region of an outer circumference of the main hammer body so that the outer contour of the main hammer body can, from at least one standpoint, be more freely embodied than one without a decoupling means; for example, the decoupling means can be advantageously used to hold a sealing means so that in the region of the sealing means, the main hammer body can be more freely embodied in terms of its dimensions, etc. It is particularly advantageous, though, if the decoupling means is provided to at least partially decouple an outer dimension of the main hammer body from a guide means of the hammer device and if the decoupling means is advantageously situated between the main hammer body and a guide means of the hammer device. The term “guide means” in this context is understood in particular to be a means in which the hammer device is guided, in particular a tubular component. The hammer device mass and a main hammer body geometry can be coordinated in a particularly advantageous manner, independent of a piston surface and an air cushion effective surface and/or an air cushion geometry and it is easily possible to achieve an advantageous hammer mechanism characteristic value composed of the maximum hammer device surface dimension, cubed and divided by the hammer mechanism mass.

The decoupling means can be manufactured of various materials deemed appropriate by those skilled in the art, for example it can advantageously be manufactured of a self-lubricating material, a plastic, a metal, a composite material, etc. In another embodiment of the invention, the decoupling means is manufactured out of a lighter material than the main hammer body, which makes it advantageously possible to achieve a low mass of the hammer device with a large effective surface.

According to another embodiment, the coupling and/or the decoupling means is/are embodied to exert an at least partial vibration-damping action. The phrase “at least partial vibration-damping action” is understood in particular to mean that during operation, the coupling and/or the decoupling means itself transmit(s) a low amount of vibration than a corresponding distance within a one-piece metallic body, particularly due to the fact that a vibration-damping and/or vibration-insulating relative movement is permitted between the decoupling means and the main hammer body and/or within the decoupling means, for example via a form-locking engagement and/or by means of an elastic material, so that in particular, a vibration of the main hammer body during operation is damped by at least 10%, preferably greater than 30%, and particularly preferably by greater than 60% at a point in the decoupling means that transmits the vibration to the outside. A corresponding embodiment can increase comfort even further.

If the coupling includes at least one connection that is manufactured by being vulcanized in place, then it is simple to provide an advantageously reliable connection, in particular between the main hammer body and the decoupling means, and to simultaneously achieve an advantageous vibration damping.

If the decoupling means has at least one guide surface, then the decoupling means can advantageously be used to improve the guidance and/or to reduce the friction, for example by being made of a self-lubricating material, etc.

If the decoupling means has at least two guide surfaces spaced apart from each other in the axial direction, then it is possible to reduce weight and assure an advantageous guidance.

According to another embodiment, the hammer device has at least one guide rib which permits the hammer device to be guided in a guide means with a large internal dimension and nevertheless, makes it possible to achieve an advantageously low hammer device mass.

If the hammer device is embodied as stepped, then this in turn makes it possible to achieve degrees of freedom with regard to its mass and external design. The term “stepped hammer device” is particularly understood in this connection to mean that the hammer device, due to its stepped design, has various guidance dimensions, in particular various guidance diameters. In this connection, a characteristic value that is comprised of a theoretical diameter in a non-stepped cylindrical design of the same mass, divided by a maximum hammer device surface dimension, is advantageously less than 0.95, preferably less than 0.8, and particularly preferably less than 0.7, while a characteristic value that is comprised of a length of the hammer device, divided by a maximum hammer device surface dimension, is advantageously less than 3, preferably less than 2.5, and particularly preferably less than 2.

According to another embodiment, a hammer device characteristic value, which is composed of the maximum hammer device surface dimension, cubed and divided by the hammer device mass, is greater than 200 mm³/g, preferably greater than 220 mm³/g, and particularly preferably greater than 240 mm³/g. In this context, the term “hammer device surface dimension” is understood in particular to mean a straight diagonal of a surface—preferably of an effective surface oriented toward the piston and cooperating with the gas volume—such as a diameter, an ellipse length, a polygon diagonal, etc.

By turning away from the established theory of designing a hand-held power tool device—in which a hammer mechanism is provided with characteristic value of approx. 160 mm³/g for the sake of compactness—and in fact designing one with a hammer mechanism characteristic value of greater than 200 mm³/g, preferably greater than 220 mm³/g, and particularly preferably greater than 240 mm³/g, it is possible to achieve particularly valuable properties with a view to reducing a heat generation in the hammer mechanism. In addition, a corresponding embodiment according to the invention also has a particularly advantageous effect on the comfort properties of the hand-held power tool hammer mechanism.

The heat generation can be advantageously reduced further and the comfort properties can be advantageously increased further if the hammer mechanism characteristic value is greater than 280 mm³/g, preferably greater than 320 mm³/g, and particularly preferably greater than 380 mm³/g.

If the hammer mechanism characteristic value is less than 2000 mm³/g, then a particularly low heat generation and a particularly high degree of comfort can be achieved while taking up an acceptable amount of space.

According to another embodiment, the hand-held power tool hammer mechanism is designed so that during operation, a maximum gas pressure in the gas volume is less than 10 bar, advantageously less than 8 bar, and particularly advantageously less than 6 bar, which likewise has a particularly advantageous effect on the heat generation and comfort properties of the hand-held power tool hammer mechanism. A corresponding pressure reduction in relation to known hand-held power tool hammer mechanisms can in particular be achieved by embodying the hand-held power tool hammer mechanism with a hammer mechanism characteristic value according to the present invention, but additionally or alternatively also through other measures deemed appropriate by those skilled in the art.

The hammer device and the piston can have effective surfaces of various shapes deemed appropriate by those skilled in the art, e.g. rectangular, elliptical, symmetrical, or asymmetrical effective surfaces, etc. The “effective surface” of the hammer device is understood in particular to mean the surface of the hammer device oriented toward the piston and the “effective surface” of the piston is understood to mean the surface of the piston oriented toward the hammer device, i.e. the surfaces cooperating with the gas volume. It is advantageous, however, if a maximum hammer device effective surface dimension deviates from a minimum hammer device effective surface dimension by less than 30% and it is particularly advantageous for the maximum to deviate from the minimum by less than 20%; it is particularly preferable, however, if the hammer device and/or the piston have/has a round effective surface, which gives the hand-held power tool hammer mechanism a particularly simple structure and makes it inexpensive to manufacture. The maximum hammer device surface dimension is preferably constituted by a diameter of the effective surface of the hammer device. In addition, the dimensions of the hand-held power tool hammer mechanism are advantageously designed so that in a so-called hammering position in which the hammer device strikes against a tool or hammer pin during operation and the piston is situated in its front end position oriented toward the hammer device, a distance between the effective surface of the piston and the effective surface of the hammer device corresponds at least essentially to approximately the maximum hammer device surface dimension and/or the diameter of the effective surface of the hammer device, i.e. advantageously has a deviation of less than 30%, preferably less than 20%, and particularly preferably less than 10%, which also particularly explains why, in the calculation of the hammer device characteristic value, the maximum hammer device surface dimension is not simply squared, but is instead cubed.

Preferably, it is also possible to reduce costs if the effective surfaces of the piston and the hammer device correspond at least essentially to each other, i.e. have a deviation, in particular a size deviation, of less than 5%. Basically, however, the effective surfaces of the piston and the hammer device can also be different in size and shape.

According to another embodiment, the hand-held power tool hammer mechanism has an eccentric drive mechanism supported at one end and/or a hammer mechanism transmission equipped exclusively with spur gear teeth, which makes it possible to use inexpensive components advantageously embodied for their comfort properties. The embodiment according to the invention is also suited, however, for hand-held power tools with drive units that operate in a manner alternative to an eccentric drive, e.g. for hand-held power tools with a so-called wobble shaft.

In another embodiment of the invention, the hand-held power tool hammer mechanism includes at least one control opening that is provided to control the gas volume and that is coupled to a motor compartment. The term “provided” is understood in particular to mean “equipped” and/or “designed”. The term “coupled” in this context is understood in particular to mean a fluidic coupling so that the gas of the gas volume can flow into the motor compartment via the control opening and/or the gas volume can be supplied with gas from the motor compartment. In addition, the term “motor compartment” is understood in particular to mean a transmission compartment, a lubrication oil compartment, a motor compartment, etc. and/or in particular, a chamber that is cut off at least in one sense from the outside, i.e. from the surroundings of a hand-held power tool, and is for example at least essentially connected to the surroundings of the hand-held power tool exclusively via pressure compensation means.

Through a corresponding embodiment, it is possible to avoid at least a direct gas exchange between the gas volume and the surroundings of the hand-held power tool and accompanying losses in comfort as well as increases in environmental impact.

Other advantages ensue from the following description of the drawings. The drawings show exemplary embodiments of the invention. The drawings, specification, and claims contain numerous defining characteristics in combination. Those skilled in the art will also suitably consider the defining characteristics individually and unite them in other meaningful combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a hand-held power tool embodied in the form of a rotary hammer, with a schematically depicted hand-held power tool hammer mechanism,

FIG. 2 shows a detail of an alternative hand-held power tool hammer mechanism with a hammer device that includes a decoupling means that is vulcanized in place,

FIG. 3 shows a detail of an alternative hand-held power tool hammer mechanism with a hammer device that includes a decoupling means that is coupled to it in a form-locked fashion,

FIG. 4 shows a detail of an alternative hand-held power tool hammer mechanism with a stepped hammer device,

FIG. 5 shows a detail of an alternative hand-held power tool hammer mechanism with a different stepped hammer device,

FIG. 6 shows a detail of an alternative hand-held power tool hammer mechanism with a decoupling means that performs a holding function for a sealing means,

FIG. 7 shows a detail of an alternative hand-held power tool hammer mechanism with a different decoupling means that performs a holding function for a sealing means,

FIG. 8 shows a detail of an alternative hand-held power tool hammer mechanism with a hammer device that includes a stepped main hammer body, without a decoupling means,

FIG. 9 shows a detail of an alternative hand-held power tool hammer mechanism with a hammer device that has guide ribs,

FIG. 10 shows the hammer device from FIG. 9, viewed in a direction labeled X in FIG. 9,

FIG. 11 shows a detail of an alternative hand-held power tool hammer mechanism with a cup-shaped hammer device, and

FIG. 12 shows a detail of an alternative hand-held power tool hammer mechanism with a different cup-shaped hammer device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a hand-held power tool embodied in the form of a rotary hammer, with a hand-held power tool hammer mechanism according to the present invention. The hand-held power tool hammer mechanism includes a hammer device 10 a, which can be driven with a piston 12 a via a gas volume 14 a. The hammer device 10 a and the piston 12 a are guided in a shared cylindrical guide means 32 a embodied in the form of a hammer tube and have corresponding effective surfaces 52 a, 54 a.

The piston 12 a can be driven by an electric motor 100 a via a hammer mechanism transmission 22 a, which is comprised exclusively of spur gears, and via an eccentric drive mechanism 20 a. The eccentric drive mechanism 20 a is supported at only one end; an eccentric pin 46 a is supported in its longitudinal direction only at an end oriented toward the electric motor 100 a by means of a spur gear 48 a and by means of a bearing axle 50 a coupled to the spur gear 48 a.

According to the present invention, the hand-held power tool hammer mechanism has a hammer mechanism characteristic value Sa of approx. 500 mm³/g, which is composed of the maximum hammer device surface dimension 16 a, cubed and divided by the hammer device mass 18 a. The hammer device surface dimension 16 a here is constituted by a diameter of a cylindrically embodied main hammer body 30 a or is advantageously constituted by a diameter of the effective surface 52 a of the hammer device 10 a.

During operation, a user pushes a tool 56 a of the hand-held power tool against an item to be machined. This slides the tool 56 a, a hammer pin 58 a, and the hammer device 10 a from their idle positions toward the piston 12 a and into their hammering positions, as a result of which the main hammer body 30 a closes control openings 24 a in the guide means 32 a so that a pressure required to drive the hammer device 10 a can build up in the gas volume 14 a between the piston 12 a and the hammer device 10 a. The control openings 24 a are fluidically coupled directly to a motor compartment 26 a constituted by a lubrication oil compartment, as schematically depicted by a conduit 62 a. The motor compartment 26 a is connected to the surroundings of the hand-held power tool exclusively via pressure compensation conduits, not shown in detail, thus preventing a direct gas exchange between the gas volume 14 a and the surroundings of the hand-held power tool.

The hand-held power tool hammer mechanism is depicted in a so-called hammering position in which the hammer device 10 a is just beginning to strike the hammer pin 58 a and the piston 12 a is situated in its front end position oriented toward the hammer device 10 a. In this connection, an axial distance 64 a between the effective surfaces 52 a, 54 a of the hammer device 10 a and piston 12 a in the hammering position corresponds approximately to the hammer device surface dimension 16 a and in particular to the diameter of the effective surface 52 a of the hammer device 10 a. During operation, a maximum gas pressure of approximately 4 to 5 bar builds up inside the gas volume 14 a.

FIGS. 2 through 11 show details of alternative hand-held power tool hammer mechanisms. Components that remain essentially the same are basically provided with the same reference numerals; the letters a-k are added to the reference numerals in order to differentiate among the exemplary embodiments. In addition, with regard to defining characteristics and functions that remain the same, reference can be made to the description of the exemplary embodiment in FIG. 1 and to the respective, previously described exemplary embodiments. The description below will essentially be limited to the differences in relation to the exemplary embodiment in FIG. 1 and the previously described exemplary embodiments.

The hand-held power tool hammer mechanism in FIG. 2 has a hammer device 10 b that includes a cylindrical main hammer body 30 b and two annular decoupling means 28 b, 28 b′ that are provided to dimensionally decouple an outer dimension of the main hammer body 30 b from a guide means 32 b constituted by a hammer tube of the hammer device 10 b. The decoupling means 28 b advantageously constitutes part of an effective surface 52 b of the hammer device 10 b, which surface is oriented toward the piston 12 b and cooperates with a gas volume 14 b. It would also be essentially conceivable for a decoupling means to constitute an entire effective surface of a hammer device that cooperates with a gas volume.

The hammer device 10 b includes couplings 34 b, 34 b′ between the decoupling means 28 b, 28 b′ and the main hammer body 30 b, which couplings are provided to couple the main hammer body 30 b to the decoupling means 28 b, 28 b′ in an at least largely synchronous fashion during a flight phase of the main hammer body 30 b or the hammer device 10 b, i.e. except for a vibration-damping relative motion. The couplings 34 b, 34 b′ are embodied to exert a vibration-damping action and include connections that are manufactured by being vulcanized in place and/or the decoupling means 28 b, 28 b′ are vulcanized onto the main hammer body 30 b.

The main hammer body 30 b is comprised of steel, whereas the decoupling means 28 b, 28 b′ is comprised of a material lighter than steel, e.g. plastic.

Each of the decoupling means 28 b, 28 b′ constitutes a guide surface 36 b, 38 b by means of which the hammer device 10 b is guided inside the tubular guide means 32 b constituted by the hammer tube; the guide surface 38 b of the decoupling means 28 b is interrupted by a groove 66 b for a sealing ring 68 b.

According to the present invention, the hand-held power tool hammer mechanism in FIG. 2 has a hammer mechanism characteristic value Sb of approx. 500 mm³/g, which is composed of the maximum hammer device surface dimension 16 b, cubed and divided by the hammer device mass 18 b. The hammer device mass 18 b here is composed in particular of the masses of the decoupling means 28 b, 28 b′ and the main hammer body 30 b together. The hammer device surface dimension 16 b is advantageously constituted by a diameter of the effective surface 52 b of the hammer device 10 b.

The hand-held power tool hammer mechanism also includes a hammer pin device 58 b that has a main hammer pin body 58 b′ and an annular decoupling means 60 b via which the hammer pin device 58 b is guided in the guide means 32 b constituted by the hammer tube. The decoupling means 60 b here is manufactured out of a lighter material than the main hammer pin body 58 b′ itself, in particular of plastic, whereas the main hammer pin body 58 b′ is manufactured out of steel. The decoupling means 60 b and the main hammer body pin 58 b′ are coupled in a form-locking manner in the axial direction by means of a snap ring 70 b, which engages with play in a groove 72 b of the decoupling means 60 b and in a groove 74 b of the main hammer pin body 58 b′.

The hand-held power tool hammer mechanism in FIG. 3 has a hammer device 10 c that has an essentially cylindrical main hammer body 30 c and an essentially annular coupling means 28 c that serves to dimensionally decouple an outer dimension of the main hammer body 30 c from a guide means 32 c constituted by a cup-shaped piston 12 c of the hammer device 10 c. The decoupling means 28 c advantageously constitutes part of an effective surface 52 c of the hammer device 10 c, which is oriented toward an effective surface 54 c of the cup-shaped piston 12 c and cooperates with a gas volume 14 c.

The hammer device 10 c includes a coupling 34 c between the decoupling means 28 c and the main hammer body 30 c, which is provided to couple the main hammer body 30 c to the decoupling means 28 c in an at least largely synchronous fashion during a flight phase of the main hammer body 30 c or the hammer device 10 c. The coupling 34 c is embodied in a vibration-damping fashion; in fact, the decoupling means 28 c and the main hammer body 30 c are coupled by means of rubber annular damping elements 76 c, 78 b, a snap ring 80 c, a contact disk 82 c, an extension 84 c formed onto the decoupling means 28 c, and a form-locking engagement that intentionally permits a limited degree of relative motion.

The decoupling means 28 c is constituted by two guide surfaces 36 c, 38 c that are spaced apart from each other in the axial direction and guide the hammer device 10 c inside the guide means 32 c comprised of the cup-shaped piston 12 c; the guide surface 38 c is interrupted by a groove 66 c for a sealing ring 68 c. The cup-shaped piston 12 c is guided in a hammer tube 86 c.

FIGS. 4 and 5 show hand-held power tool hammer mechanisms with stepped hammer devices 10 d, 10 e and with hammer devices 10 d, 10 e that have different guide diameters 88 d, 88 e, 90 d, 90 e; the guide diameters 90 d, 90 e respectively correspond to the maximum hammer device surface dimensions 16 d, 16 e. The hammer device 10 d has a stepped main hammer body 30 d, which has two cylindrical main forms with different diameters and which, in the region of its smaller diameter on a side oriented away from a piston 12 d, is guided by means of a decoupling means 28 d in a guide means 32 d comprised of a hammer tube. The hammer device 10 e has a cylindrical main hammer body 30 e with a continuous diameter 88 e, which, at its end oriented toward a piston 12 e, is guided by means of a decoupling means 28 e in a guide means 32 e comprised of a hammer tube. The decoupling means 28 e here constitutes a part of an effective surface 52 e of the hammer device 10 e that cooperates with a gas volume 14 e. At its end oriented away from the piston 12 e, the main hammer body 30 e is guided directly in the guide means 32 e.

The hand-held power tool hammer mechanism in FIG. 6 has a hammer device 10 f with a main hammer body 30 f and a decoupling means 28 f that is provided to dimensionally decouple the main hammer body 30 f. To this end, the decoupling means 28 f is provided, together with the main hammer body 30 f, to form a groove 66 f for a sealing ring 68 f. The presence of the decoupling means 28 f permits the main hammer body 30 f to be embodied as thin-walled in the axial direction in the region of its guide surface 92 f, but the sealing ring 68 f can still be advantageously situated in this region. In the direction extending from a piston 12 f toward a tool that is not shown in detail, the decoupling means 28 f is situated after the guide surface 92 f of the hammer device 10 f or main hammer body 30 f oriented toward the piston 12 f.

It is also conceivable, however, for a decoupling means 28 g to be situated in a direction extending from a piston 12 g toward a tool that is not shown in detail before a guide surface 92 g of a main hammer body 30 g oriented toward the piston 12 g, as depicted in FIG. 7. By contrast with the exemplary embodiment in FIG. 6, a groove 66 g is formed exclusively by the decoupling means 28 g.

The hand-held power tool hammer mechanism shown in FIG. 8 has a hammer device 10 h with a stepped main hammer body 30 h, without a decoupling means. The hammer device 10 h here has a characteristic value of approx. 0.5, which is composed of a theoretical diameter 94 h in a non-stepped cylindrical design of equal mass, divided by a maximum hammer device surface dimension 16 h and a characteristic value of approx. 1.5, which is composed of a length 96 h of the hammer device 10 h, divided by the maximum hammer device surface dimension 16 h. The maximum hammer device surface dimension 16 h corresponds to a diameter of an effective surface 52 h of the hammer device 10 h cooperating with a gas volume 14 h.

The hand-held power tool hammer mechanism shown in FIGS. 9 and 10 has a hammer device 10 i with three guide ribs 40 i, 42 i, 44 i distributed uniformly over its circumference. The guide ribs 40 i, 42 i, 44 i are integrally formed onto a main hammer body 30 i.

The hand-held power tool hammer mechanism in FIG. 11 has a cup-shaped hammer device 10 j or cup-shaped main hammer body 30 j, with a cup opening oriented toward a hammer pin 58 j. In a hammering position shown, the hammer pin 58 j protrudes into the cup-shaped hammer device 10 j and, with an end oriented toward the cup opening, comes into contact with a cup bottom of the hammer device 10 j.

The hand-held power tool hammer mechanism in FIG. 12 has a double cup-shaped or cross-sectionally H-shaped hammer device 10 k or a double cup-shaped main hammer body 30 k, with one cup opening oriented toward a piston 12 k and one cup opening oriented toward a hammer pin 58 k. In a hammering position shown, an extension 98 k of the piston 12 k oriented in the axial direction protrudes into the cup-shaped hammer device 10 k and the hammer pin 58 k protrudes into the cup-shaped hammer device 10 k and comes into contact with a side of a cup bottom of the hammer device 10 k oriented toward it. It is also basically conceivable for a hammer pin to be provided that has only one cup opening oriented toward a piston.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a hand-held power tool hammer mechanism, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 

1. A hand-held power tool hammer mechanism, comprising a hammer device having a main hammer body; means forming a gas volume; a piston driving said hammer device via said gas volume, said hammer device having at least one decoupling means provided for dimensionally decoupling said main hammer body of said hammer device, and a coupling between said decoupling means and said main hammer body for coupling said main hammer body to said decoupling means in an at least largely synchronous fashion during a flight phase of said main hammer body.
 2. A hand-held power tool as defined in claim 1; and further comprising guide means for said hammer device, said decoupling means being configured to at least partially decouple an outer dimension of said main hammer body from said guide means.
 3. A hand-held power tool as defined in claim 1, wherein said decoupling means is composed of a lighter material than said main hammer body.
 4. A hand-held power tool as defined in claim 1, wherein an element selected from the group consisting of said coupling, said decoupling means, and both is configured to exert an at least partial vibration-damping action.
 5. A hand-held power tool as defined in claim 1, wherein said coupling includes at least one connection which is configured as a vulcanized-in-place connection.
 6. A hand-held power tool as defined in claim 1, wherein said decoupling means has at least one guide surface.
 7. A hand-held power tool as defined in claim 6, wherein said decoupling means has another such guide surface, so that said guide surfaces are spaced from each other in an axial direction.
 8. A hand-held power tool as defined in claim 1, wherein said hammer device has at least one guide rib.
 9. A hand-held power tool as defined in claim 1, wherein said hammer device is configured as a stepped hammer device.
 10. A hand-held power tool as defined in claim 1, wherein a hammer mechanism characteristic value which is composed of a maximum device surface dimension cubed and divided by a hammer device mass is greater than 200 mm³/g.
 11. A hand-held power tool as defined in claim 10, wherein the hammer mechanism characteristic value which is composed of a maximum device surface dimension cubed and divided by a hammer device mass is greater than 220 mm³/g.
 12. A hand-held power tool as defined in claim 10, wherein the hammer mechanism characteristic value which is composed of a maximum device surface dimension cubed and divided by a hammer device mass is greater than 240 mm³/g.
 13. A hand-held power tool as defined in claim 1, wherein a hammer mechanism characteristic value which is composed of a maximum device surface dimension cubed and divided by a hammer device mass is greater than 280 mm³/g.
 14. A hand-held power tool as defined in claim 13, wherein the hammer mechanism characteristic value is greater than 320 mm³/g.
 15. A hand-held power tool as defined in claim 13, wherein the hammer mechanism characteristic value is greater than 380 mm³/g.
 16. A hand-held power tool as defined in claim 1, wherein a hammer mechanism characteristic value which is composed of a maximum device surface dimension cubed and divided by a hammer device mass is less than 2000 mm³/g.
 17. A hand-held power tool as defined in claim 1, wherein said gas volume has a maximum gas pressure during operation which is less than 10 bar.
 18. A hand-held power tool as defined in claim 17, wherein said gas volume has the maximum gas pressure during operation which is less than 6 bar.
 19. A hand-held power tool as defined in claim 1; and further comprising an eccentric drive mechanism supported at one end.
 20. A hand-held power tool as defined in claim 1; and further comprising a hammer mechanism transmission composed exclusively of spur gear teeth.
 21. A hand-held power tool as defined in claim 1; and further comprising at least one control opening provided for controlling the gas volume and coupled to a motor compartment.
 22. A hand-held power tool, comprising a hand-held power tool hammer mechanism including a hammer device having a main hammer body; means forming a gas volume; a piston driving said hammer device via said gas volume, said hammer device having at least one decoupling means provided for dimensionally decoupling said main hammer body of said hammer device, and a coupling between said decoupling means and said main hammer body for coupling said main hammer body to said decoupling means in an at least largely synchronous fashion during a flight phase of said main hammer body. 